Cartridge guide and stop for machine guns



March 13, 1951 w. CLAYTON CARTRIDGE GUIDE AND STOP FOR MACHINE GUN Filed Feb. 16, 1945 Patented Mar. 13, 1951 CARTRIDGE GUIDE AND STOP FOR MACHINE GUNS William Clayton, Bristol, Conn., assignor to Associated Spring Corporation, Bristol, Conn., a

corporation of Delaware Application February 16, 1945, Serial No. 578,136

1 Claim.

This invention relates to machine guns and, more particularly, to means for positioning successive cartridges in perfectly uniform positions within the gun as they are fed thereto, whereby the operation of the gun will not be disturbed by improper positioning of the cartridges.

In machine guns of the type to which the invention particularly relates, the main or breech casing of the gun, from which the barrel extends, is provided with a transverse feed passage through which a cartridge belt is fed. There is also provided within the breech casing a longitudinally movable extractor which engages each cartridge as it arrives at the lateral center of the feed passage and withdraws it rearwardly from the belt so that it may thereafter be pushed forwardly into the firing chamber. Each cartridge is provided at its rear end with a circumferential groove forming an annular shoulder which is engaged by the extractor. In order that the gun may operate without unintended interruption it is necessary that each cartridge arriving at a lateral position to be extracted from the belt is located longitudinally of the gun within the feed passage that the extractor will grasp the annular shoulder thereon. It will be apparent that if the cartridge is forward of its proper position in the feed passage the extractor will not engage the shoulder, the cartridge Will not be withdrawn from the belt and the operation of the gun will be stopped.

Various means have heretofore been proposed for properly positioning the cartridges longitudinally of the feed passage. The usual and most common means consists in a cam or guide face located at the front end of the feed passage and which is engaged by the forward end of each cartridge as it moves into the passage and which is designed to move each cartridge to a predetermined, proper position longitudinally of the feed passage. The proper operation of this device depends, however, on all of the cartridges being of a common designed length, which will be suincient to cause the rear end of each to be properly positioned to be engaged by the extractor. It has been found in actual practice, however, that for a variety of reasons a cartridge will often be shorter than its designed length, whereby the cam face, although performing its specified function, will be ineffective to properly position the rear end of the cartridge within the feed passage and with respect to the extractor.

The fact that the described cam faces are ineffective to properly position the cartridges under all situations has led to proposals to provide additional cartridge positioning means which are operative on the cartridge or on the belt or on both of these. One principal disadvantage of such proposed devices has been, however, that all of them required some modification of the gun, for example by the attachment of additional parts or the removal or change of existing parts. Any such modification of the gun is undesirable for obvious reasons.

It is therefore one object of this invention to provide a simple, easily-installed device for positioning successive cartridges passing into the feed passage of a machine gun in a predetermined and proper location in which the annular shoulder at the rear end thereof may be engaged and grasped by the extractor. The principal object is to provide such a device which may be installed without any modification of any part of the gun, and which may be quickly and easily installed, removed or replaced without the removal and/or replacement of any part of the gun.

Other objects and features of novelty of my invention will be made apparent by the following description and the annexed drawings which are only illustrative of the invention.

Referring to the drawin s, in which similar reference numerals refer to like parts,

Fig. 1 is a side view of part of the breech casing and barrel of a machine gun, showing a cartridge positioning device according to my invention attached thereto in operative position;

Fig. 2 is a perspective view of the cartridge positioned device of Fig. 1;

Fig. 3 is a view which is similar to Fig. l and which shows a preferred form of cartridge positioning device according to my invention;

Fig. 4 is a perspective view of the cartridge positioning device of Fig. 3.

The machine gun parts illustrated in Figs. 1 and 3 of the drawings form only a part of the entire gun but inasmuch as the structure of such guns is well-known no additional illustration is believed to be necessary. Reference may be had to the. U. S. patent to John M. Browning, No. 1,293,021, and U. S. reissue patent to Frederick T. Moore and Christen Pfeifier, No. 19,159, for a more complete disclosure of such a gun.

In Fig. 1 of the drawings the main or breech casing of a machine gun is shown at 2 and comprises a box-like structure containing the breech mechanism of the gun and from which a barrel 4 extends forwardly. The top of the breech casing is formed and provided by a trunnion block 8 at the front of the casing and to the rear of which is pivotally connected a cover 10 which extends to the rear end of the breech casing where means are provided to lock it in closed position. The breech casing is provided with a feed passage l2 extending transversely of the casing and which is of approximately the length of a cartridge, whereby a cartridge belt may be fed through the casing from either side of the gun to the other. The forward end of the feed passage lies below the trunnion block 8, while the larger rear part of the passage is below the cover it]. A transverse opening M. isprovided in the lower side of the cover within which is positioned mechanism of known construction and operation for moving the cartridge belt in the described manner. At the forward end of the feed passage cam surfaces [5 extend from each side of the breech casing and are engaged by the cartridges moving into the feed passage for the purpose of insuring that the forward ends of the cartridges move into the passage. In Fig. l a cartridge [6, which is held Within the links is of a cartridge belt of the disintegrating type. is shown Within the feed passage 12'. This cartridge, in accordance with. known practice and structure, has a circumferential groove 20 adjacent the rear end thereof which defines an annular shoulder l2v at the rearmost end of the cartridge.

In accordance with the known and usual operation of such a gun the cartridge belt is moved by the feed mechanism in opening [4 until the, cartridge [6 reaches a central position within the feed passage. The extractor device (not shown) then moves forwardly to. engage and grasp the shoulder 22, then moves rearwardly to withdraw the cartridge from the links [.8', then downwardly, and then forwardly to insert. the cartridge in the firing chamber. It will be apparent that if the shoulder 22 and groove 20 of the cartridge are not properly positioned longitudinally of the gun Within the feed passage the extractor will not engage the shoulder and the operation of the gun will be interrupted and cannot be restored until the cartridge is moved, rearwardly to properly position the groove and shoulder.

Means are. provided by the present invention for engaging each cartridge as it moves into. the feed passage and moving. it in such away that the groove 20 and shoulder 22' of each, cartridge occupy a predetermined position longitudinally of the gun within the feed. passage and in which the shoulder may be engaged by the extractor. Such means engage the links [8 of the disintegrating belt which holds the cartridges and, therefore makes use of the observed fact that the distance between the forward. edge of the links and the groove 20 is substantially constant for all cartridges. In this connection, it may be noted that differences in the lengths of cartridges have been found to be due in almost all cases to differences in the extent to which the projectile part of the cartridge is driven into the casing part. This accounts, of course, for the fact that devices engaging only the forward end of the projectile are ineffective to locate the groove 20 and shoulder 22 in a constant position longitudinally of the gun within the feed passage and with respect to the extractor.

One embodiment of my invention is illustrated in Figs. 1 and 2 and comprises a device, which may be formed or stamped from, sheet metal, having an elongated, narrow fiat part 30 having upturned ears 32', 34 at the opposite ends thereof within which are formed aligned openings 35. A substantially flat member 40 extends rearwardly from the part 30 and these parts are resiliently connected by a part 42 of curved cross-section. The rear edge 44 of the flat member 40 is provided with arcuate upwardly-struck parts 46, 4B, 50 at the ends and center thereof, respectively. Struck-up lugs 45 are provided at the opposite ends of the flat part 30.

The described short round stop is attached to the breech casing by passing the bolt 38, by which the cover ID is pivotally connected to the trunnion block 8, through: the aligned openings in th ears 32,. 314,. the parts 30, 42, 40 of the stop device being positioned beneath the trunnion block and cover with the part 60 extending rearwardly. The lugs 55 are. received within aligned apertures in the opposite sides of the lower face of the trunnion block and serve to fix the stop device against undesired movement. The dimensions of the parts are such that the rearward edge 44 of the member 40 is in such a position that when the-forward edge of the forward link I8 surrounding a cartridge within thefeed passage rides against such edge the cartridge is moved longitudinally of the feed passage to such a position that the groove 28- and shoulder 22 thereof are exactly and properly positioned for engagement and grasping bythe extractor, regardless of the distance to which the projectile of the cartridge projects forwardly fromthe end of the casing. One or the other of the upwardly indented parts 26, 48 at the ends of the member 45) receive the cartridge as it moves into the feed passage, while the upwardly indented part 50 at the center of the member 30 positions the cartridge at the center of the feed passage, thus additionally insuring that it wi-ll be' properly positioned with respect to the extractor.

In operation, as the cartridges'are fed into the feed passage, being connected by the links of the disintegrating belt, the camming edge 44 of the stop device engages the forward edge of the link belt and moves the belt and cartridge to such position that when the cartridge reaches the transverse center of the feed passage the extractor will engage in the groove 20 regardless of the overall length of the cartridge. Because of the flexibility of the device, due both to its construction and to the spring steel of which it is preferably' made, the member 40 rises and falls with any changes inheight of the belt and the cartridges held thereby, thus closely hugging the cartridges and assuring that the camming edge 44 will engage the forward edge of the forward link of the belt.

In Figs. 3 and 4 of the drawings there is disclosed. a preferred embodiment of the invention which is constructed and adapted for attachment to the cover Ill instead of to the trunnion block, as is the case with the device of Figs. 1 and 2. This device is preferably formed of spring steel and comprises a flat member 5| having an elongated opening 52 therein 'andhaving upturned ears 54, 5B at'the opposite ends thereof, the upper ends of which ears are turned inwardly to form flanges 58, 6B, Beneath the flat member 5| is a second flat member 62 which is substantially parallel to the-member 51 and is connected thereto by a part 64 of C-shaped; cross-section, whereby the member 62 may" be resiliently moved vertically with respect to; the member iii. The free edge 66 of the member 62 is curved longitudinally thereof and the opposite ends of the member 62 are deformed upwardly to" form flanges 68, 1B which assist in guiding the. cartridges entering the feed passage to aposition below'the plate 62:

As disclosed in Fig. 3 of the drawing this embodiment of the invention is assembled to the cover In by engaging the ear 54 and flange 58 over one side and the top of the cover adjacent the hinge and the ear 56 and flange 60 over the other side and the top of the cover. The fiat member 5| tightly engages the bottom of the cover, while a bracket 12 which is a standard part of the .50 caliber Browning machine gun, fits into the elongated opening 52 in member 5| in order to prevent movement of the member longitudinally of the cover. The lower flat member 62 lies under the bottom of the cover and under the bracket 12. The dimensions of the parts are such that the camming edge 66 of the lower member fiz is so positioned in the feed passage that when a belt of cartridges moves into the passage the camming edge 66 will engage the forward edge of the forward link of the belt and will move the belt and the cartridges therein to such a position within the passage that when the cartridge I 5 reaches the transverse center of the feed passage the extractor groove 20 of the cartridge will be exactly and properly positioned for engagement by the extractor. Due to the resilient connection 64 between the members 5| and 62, the member 62 may move up and down to accommodate any variation in the height of the belt and cartridges, thus causing a constant engagement between the edge 66 and the top of the cartridge cases. The camming edge 66 is so curved that the most rearward point thereof is at its center whereby, regardless of the position of the belt with respect to the feed passage, as the belt moves into the passage the forward edge of the forward link of the belt will be progressively engaged by the camming edge 66, thus progressively forcing the belt and cartridges rearwardly until the proper position at the center of the feed passage is reached.-

I claim:

In a short-round corrector for a machine gun provided with a receiver having an ammunition feed passage through which an ammunition belt of the disintegrating link type may pass from either side of the gun, an upper plate, a lower plate, C-shaped spring means resiliently connecting the forward edges of said plates so that said plates lie in superposed parallel relation, the rearward edge of said lower plate being curved symmetrically from its center to each end for engagement with the forward top edge portion of each successive belt link as it is moved into cartridgeextracting position in said feed passage, an ear extending upwardly from each end of said upper plate to embrace the sides of the gun receiver therebetween, an inwardly-turned flange on the upper end of each ear to fit overthe top of the gun receiver and hold said plates in operative position within the ammunition feed passage of the gun, and an upwardly-turned flange on each end of said lower plate, said corrector being formed in one piece of spring sheet metal, there being an elongated transverse slot in said upper plate to fit upwardly about a bracket of the gun, depending within said feed passage, when said flanged ears are in position embracing the sides of the gun receiver, whereby to prevent forward and rear movement of said corrector relatively to the gun.

WILLJAM CLAYTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,101,086 Moore Dec. 7, 1937 2,121,794 Green l June 28, 1938 2,327,922 Moore et al Aug. 24, 1943 2,476,552 Katz July 19, 1949 2,478,219 Young Aug. 9, 1949 

